2. Introducció Two surgical techniques to determine FCER Landmarks
Mesured resection technique
Balanced gap technique
Landmarks
Transepicondylar axis
Anterioposterior line
Posterior condylar line

3. Introduction Mesured resection technique Balanced gap technique
Trapezoidal flexion gap
Regardless of ligament tension
Balanced gap technique
Cut parallel to the proximal tibial cutting
Better flexion stability
Better patellar tracking
Depends on soft tissue balance
Could lead to undesirable implantation

4. Purposes
Determine femoral component rotations and laxities using a navigation system during CR TKA using balanced gap technique
Evaluate the effects of femoral rotation on knee function

5. Materials and Methods Prospective study 47 patients
Exclusion criteria:
Open knee surgery
Severe deformity (>20º varus or >30º flexion)
Other than osteoarthritis
Follow-up 54,5 months (48-68)
4 men and 40 women
Mean age 68,8 years (56-79)

6. Surgical Technique Medial parapatellar approach (Patellar eversion)
OrthoPilot navigation system
Proximal tibial cutting 0º
PCL was preserved
Tensioning device for extension gap
Release medial structures if necessary
4-in-1 cutting block parallel to the tibial resection plane
External rotation range 0-7º (Patellar tracking)

7. Surgical technique Not allowed internal rotation
ER >7º release anterior fiber of SMCL
Cemented Aesculap TKA
Patella was not resurfaced
Posterior slope 3º

8. Materials and Methods Clinical outcomes Statistics
Same physician assistant (not involved)
HSS, WOMAC, Rmotion, FT angles, Posterior femoral condyles offset, radiolucent lines
3 and 12 months and annually
Statistics
Paired Student t test
Pearson regression analysis
SPSS
Distributions were normal

9. Results Mean ER femoral component 3,8 +/-2,4º
Mean knee mechanical alignments:
0º flexion: 0,6 +/-1,1º of varus
90º flexion: 1,4 +/-2,6º of varus
Positive correlation (r:0,70 p<0,01) between FCER and varus alignment at 90º flexion
8/14 with >6º ER: more than 3º varus
2/30 with 0-5º ER: more than 3º varus
90º

10. Results Mean vr-vl laxity greater at 90º HSS and WOMAC improved
90º: 5,8 +/-1,9º
0º: 4,4 +/-1,4º
HSS and WOMAC improved
FT angles improved
Radiolucent lines 9/47

11. Discussion BG technique good alignments and stability
More FCER, more varus knee at 90º flexion
No correlation between FCER and preoperative mechanical angle
Hanada et al: Substantial varus alignment at 90º flexion
Cadaver without soft tissue release
Did not set femoral external rotation

12. Discussion Limitations Conclusion
Intraoperative laxity testing manually
Alignment was measured under non-weight-bearing conditions
Conclusion
Excessive FCER can be avoided by additional soft tissue balancing, and prevents varus malalignment